A light emitting diode (LED) is a semiconductor device that is excited to generate light in response to a current to produce light of various colors. Due to high band gap width, high luminous efficiency, high electron saturation drift speed, and stable chemical properties, group III-V compound semiconductors represented by gallium nitride (GaN) have huge application is potential in photoelectron device fields, such as high-brightness blue LED or blue lasers, and has aroused widespread concern.
From the view of structures, LEDs can be classified into normal structure, flip-chip structure and vertical structure. LEDs with the vertical structure possess advantages, like high thermal efficiency, large load current, high luminous intensity, low power consumption and long life span. Therefore, LEDs with the vertical structure as high-power LEDs draw more and more attention and are studied more and more in the industry.
Two electrodes of an LED with the vertical structure are located on a side of an epitaxial layer of the LED respectively. Through a patterned electrode, a current flows almost vertically through the epitaxial layer of the LED, and the current flowing in a lateral direction is less, which may effectively mitigate a current congestion problem, and be conducive to improvement of luminous efficiency.
However, in existing techniques, LED chips always have a complicated process and high cost.